(Cassiopeia claims that she is more
beautiful than the daughter of a god + Vanity and arrogance are traits that
are punished )
(Perseus agrees to bring a Gorgon's
head to Polydectes + Bringing a wedding present shows
respect)
(The Hyperboreans welcome Perseus
and give him the gifts he seeks + Hospitality and kindness are
admirable qualities)
(As predicted, Achsis is killed by his
grandson, Perseus + Some parts of life are controlled by
fate)
(Andromeda is offered to a serpent to
make the sea god happy + Sacrifice is important because it
makes the gods happy)
Hope this helps :)